Protective effect of electron beam irradiation in tocopherols integrity: evaluation by HPLC-fluorescence detection
Conference Paper
Overview
Overview
abstract
The high perishability is a common characteristic in mushrooms. This limitation
demands for continuous investigation to achieve an effective conservation
technology, allowing their preservation while simultaneously protecting the
main bioactive compounds and the chemical composition in general. However,
these two objectives might be more accurately achieved by combining two
technologies, instead of using a single one. Therefore, electron-beam irradiation
(up to 10 kGy) was applied to dried samples of Boletus edulis and Russula
delica, increasing previous knowledge using gamma- and electron-beam
irradiation at lower doses (up to 6 kGy) and different wild mushroom species. In
this study, an HPLC system coupled to a fluorescence detector (FP-2020; Jasco),
programmed for excitation at 290 nm and emission at 330 nm, was used to
evaluate changes in tocopherols profile among irradiated and non-irradiated
mushrooms.
The chromatographic separation was achieved with a Polyamide 11 normal phase column (250 x 4.6 mm; YMC Waters) operating at 30 °C. The mobile
phase used was a mixture of n-hexane and ethyl acetate (70:30, v/v) at a flow
rate of 1 ml/min. The compounds were identified by chromatographic
comparisons with authentic standards. Quantification was based on the
fluorescence signal response, using the internal standard method.
The vitamer quantified in highest amount was δ-tocopherol in both
mushrooms, but B. edulis presented higher total tocopherols quantities. The
effects on tocopherols profiles were significant for all quantified isoforms
(except δ-tocopherol in B. edulis). Irradiated samples tended to present higher
amounts, as it was particularly observed for 2 kGy dose in B. edulis (129 μg /100
g dw) and the 6 kGy in R. delica (87 μg /100 g dw), showing consistency with a
previous study [1]. This result might be explained by differences in free oxygen
availability inside the polyethylene bag. Overall, the applied doses might guarantee not only desinfested and decontaminated samples, but also provide
the aditional advantage of protecting one of the important bioactive lipophilic
compounds.
